The present invention relates to vision systems for bobbin stripping systems and for other automation applications, such as robotics. It is particularly useful for stripping fiberglass yarn from the dark colored bobbins used in fiberglass yarn processing.
U.S. Pat. No. 4,965,917 discloses an apparatus for use in stripping yarn from bobbins. The entire disclosure of that patent is incorporated herein by reference. Briefly, that patent discloses an apparatus including a conveyor for conveying bobbins to be stripped to a stripping station. The bobbins stop at the stripping station at which are located a plurality of vertically aligned nozzles which emit high pressure water streams. The nozzles are mounted for pivoting reciprocation about axes generally parallel with the line of travel of the conveyor. The axes are spaced from one another vertically, so that as the various nozzles reciprocate through their respective arcs, high pressure water jets are directed against the bobbin along a generally vertically extending line. The jets shear the fiberglass and wash it away, leaving a relatively clean bobbin.
The number of reciprocations of the nozzles needed to completely strip the yarn from a bobbin varies, depending upon numerous variables, including the amount of yarn still adhering to the bobbin, the dirtiness of the bobbin, the condition of the bobbin, and the operating performance of the nozzles. In the prior apparatus the conveyor carried the bobbins past the stripping station, where they were held stationary for a preset period of time for stripping. It was found that in order to assure a high level of confidence that the bobbins have been completely stripped, an inordinately long stripping period must be provided for each bobbin. That is, the preset stripping period must be long enough to strip the bobbins needing the longest period for stripping. This results is inefficient operation when stripping bobbins which do not require such long stripping periods. Setting the period to be too short results in an excessive number of bobbins not being completely stripped, requiring reworking.
One possible solution to this would be to have an operator manually watch each bobbin be stripped and actuate a switch to index the conveyor holding the bobbins when the human operator can visually detect complete stripping. While this is a theoretically feasible approach, the expense of using a human operator for such a job is undesirable. Also, this would be a very tedious job for a person to carry out. Furthermore, the environment in which the stripping takes place is subject to high pressure water sprays and flying fragments of glass yarn. The water spray forms vision-obscuring mists, so the operator may have difficulty seeing the bobbin. Adding the fact that the operator may suffer injury from the glass yarn particles makes this choice of a solution undersirable.
Accordingly, there is a need in the art for a method and apparatus for automating the stripping apparatus to assure efficient and complete stripping of the bobbins. Furthermore, there is a need for a vision system for processes of this sort to allow the vision system to operate, even in the presence of vision-obscuring by-products.